If 'If P, then Q' is a conditional statement, then 'If not Q, then not P' is its:

Which of the following methods or reasoning types legally constitute a formal logical proof in mathematics? (J) Inductive reasoning (K) Deductive reasoning (L) Geometric concepts (M) Properties of polygons

Consider the following statements: Statement 1: If a quadrilateral is a square, then all of its sides are equal. Statement 2: If all the sides of a quadrilateral are equal, then it is a square. Which of the following correctly describes the relationship between the two statements?